蠕变条件下软土微观孔隙变化特性

Variation characteristics of soft clay micropore in creep condition

研究软土蠕变过程的微结构变化可深入了解蠕变特性的内在机制。在对漳州软土进行多种蠕变试验的基础上,利用微观定量化技术,对比原状软土与蠕变条件下土样的微观孔隙,从微观角度对蠕变机制进行了解释。研究表明,土样产生蠕变变形后,孔隙大小变化遵循孔隙均匀化原理;孔隙的复杂度与定向性降低;孔隙形状趋向扁圆形发展。发现不同的蠕变试验方法下,孔隙的微结构参数对蠕变变形的敏感度是不一样的,建议针对不同的蠕变试验方法,宜采用不同的微观参数来进行微结构特征的描述。揭示了土体不同蠕变表现,实际上都是土内部结构不断改变自我调整再造的过程。通过对软土蠕变特性的本质因素的研究,可以解释宏观工程现象,为合理的蠕变本构关系提供了依据,以指导工程实践。

Through researching variation of soft clay microstructure in creep condition, we can deeply understand internal mechanism of creep characteristics. According to the micro quantitative technology and different creep tests of soft clay in Zhangzhou area, comparison between micropores of intact soil sample and soil sample in the creep condition is made for purpose of explaining creep mechanism from microcosm. Research shows that micropore size change follows theory of homogeneity, complexity and directionality decrease; pore figure trends oblate after soil occur screep deformation. Parameters of micropore have different sensitivities of creep deformation in different creep tests. It is suggested that the different micro parameters should be adopted in different creep tests for description of microstructure characteristics. Research reveals soft clay creep phenomenon is caused by soil internal structure change constantly and self-adjustment and reconstruction. Through studying the fundamental factors of soft clay creep characteristics, it is possible to interpret macroscopic phenomenon and provide evidence for reasonable constitutive relation for giving important suggestions to engineering design.